Resistance-coil.



Patented Feb. I8, |902.

A. c. EAsTwoon, RESISTANCE COIL.

(Application led Sept. 26, 1901.)

Ulu Model.)

UNITED STATES ATENT OFFICE.

ARTHUR C. EASTWOOD, OF CLEVELAND, OHIO, ASSIGNOR TOTHE ELEC- TRIOCONTROLLER AND SUPPLY COMPANY, OF CLEVELAND, OHIO, A

CORPORATION OF OHIO.

RESISTANCE-'iCOILl .SPECIFICATION forming part of Letters Patent Ivo.693,692, dated Fenway 1s, ieee.

Application filed September 26. 1901. Serial No. 76,660. (No model.)

To all whom t may conoci/n.-

Be it known that I, ARTHUR C. EAs'rwooD, a citizen of the United States,residing in Cleveland, Ohio, have invented certain Improvements inResistance-Coils, of which the following is a specification.

My invention relates to certain improvements in resistance-coils, havingfor its object provision of a self-supporting coil which while simpleand inexpensive to construct shall be durable and efficient in use, afurther object being to provide a coil which shall automatically breakor blow out any arc formed between the adjacent contact-segments formingthe terminals of a series of coils or between a segment and a contactarm or brush bearing upon the same. These objects I attain ashereinafter set forth, reference being had to the accompanyingdrawings,inwhich Figure l is a side View of my improved coil, showing itas attached to a slab of insulating material. Fig. 2 lis a sectionalview on the line 2 2, Fig. l. Fig. 3 is a side view, partly in section,of a series of my improved resistance-coils, in which is indicated themagnetic eld when an electrical current is flowing through theresistance-coils; and Fig. 4 is an end view of Fig. 3. f

In such apparatus as at present constructed the resistance is made up ofcoils, grids, or other forms mounted in a suitablev frame or case. Wiresare carried from various points in the bank of resistance to 'suitablecontacts mounted on a slab of marble, slate, or other insulatingmaterial. An arm provided with suitable brushes or contact-lin gers isarranged to make electrical contact with the abovementioned contactsegments or buttons, and motion of the arm cuts in or out sections ofthe resistance, as may be required in the operation cf the apparatus.These connections from the resistance-sections to the contactv man;7'cases destructive. Many means have been devised for combating this are,princi- `pal among them being a magnet so arranged that the poles are inproximity to lthe contacts. It is found very difficult, however, toproperly direct the lines of force from the magnet toefticiently blowout the arc. Another method consists in dividing up the requiredresistance into a great number of small partsv and providing a separatecontact for each section, thus reducing the difference ofpotentialbetween adjoining segments. This of course greatlyincreases thenumber of contact-segments, connections, dac., and whereany'considerable amount of resistance is employed becomes very costly.In my improved resistance unit the core upon which the coil is woundforms its connection to the Contact segment or plate. Henceconnecting-wires from the sections of resistance to their respectivecontact-segments are dispensed with. Further, the insulating-tube uponwhich the coil is wound supports it in position, thus again reducing thenumber of parts.4 By the selection of certain materials and combiningthem in proper relations I am enabled to disperse any are which may beformed between the contact-segments more effectively than by any meansat present known to the art. I can therefore disregard the difference ofpotential between adjoining segments and construct a given piece ofapparatus with fewer sections of resistance, and hence fewercontact-segments and connections, than has been heretofore possible.Thus by means of my invention I can greatly reduce the complication andnumber of parts, and hence the cost of any piece of apparatus in whichit is used.

In the drawings, A is a core of heat-resisting insulating material, suchas porcelain or asbestos.

B is a rod of magnetic material passing through the core and providedwith threads to accommodate at one end the nuts c and c and at the otherend tthe plate d, the nut c2, and the contact-plate e. The plate d ismade of copper, brass, or other conducting material and is threaded inplace on the rod B. The plate d at the other end of the coil isv made ofinsulating material-and is adapted the contact-button e.

to slip over the end of the rod B. The nut c when drawn up serves toclamp the various parts of the coil firmly in place ready for receivingthe turns of resistance-wire C. One end of the wire C is passedsuccessively through two holes in the insulating-plate c?, thus servingto retain it in place. The end c3 is left of sufficient length for theconnection that may be required. For ordinary series connection in abank of resistance this free end c3 is clamped under the nut c'of thenext neighboring coil. After winding the coil the otherend c4 is passedalternately through slots cl3 in the plate d and then given a turn atright angles, as is clearly shown in Fig. l. This holds the Wire inplace ready for soldering or other electrical connection to the plate d.

F is aslab of insulating material on which are mounted thecontact-buttons e. It will be readily seen that the rod B passes intothe insulating-slab and is clamped in place by a nut c2 at the base of acounterbored hole. The contact-segments, here shown as octagonalbuttons, are screwed in place on the end of the rods B. A washer d2 isplaced between the end plate d and the back of the slab F to provide asquare bearing. Supposin g the current enters the coil at the end c3, itwill pass through the Various turns of the coil to the end plate d andthence through the rod B to It islevident that the turns of the coil Care so disposed about the rod of magnetic material B thatwhen current nee', and as this is the point at which an arc may be caused by thedierence of potential between the contact-buttons they will effect;ively disrupt this arc.

In Fig. 3, Fis the insulating-slab, on which are mounted a series ofresistance-coils and their contact-buttons e e', e being the first coilin a series or bank of resistance. e2 is a dead-block of insulatingmaterial on which the contact-arm rests when the resistance is out ofcircuit. Since the form of this -contactarm has no part in thisinvention, it has not been shown. As the contact-arm passes from e to c2an arc would ordinarily be set up at this point, since the circuit isopened by this movement. To dispel this arc, a rod of magnetic materialB is magnetically connected to the rod B by the strap b, and a magneticfield thus set up through the gap between e and e2.

It will be seen that I have provided a resistance-coil which, inaddition toits other functions, acts as the blow-magnet to break any arcformed between its contact plates or buttons and the contact-arm. Thecoils are self-contained and independent of each other to an extentwhich allows the removal of individual coils in any easy man-ner. Thecontact-plates as they wear out may be cheaply and easily replaced, itonly being necessary to unscrew them from the end ot' the rod B, anoperation requiring but little time and no dismantling of the apparatus.

I claim as my invention*- 1. In a resistance-coil the combination of abody of insulating material, turns of' resistance material woundthereon, and a rod of magnetic material extending through said bodyelectrically connected to the turns of resistance material, withcontact-plates also in circuit with the said coil and within themagnetic iield passing through said rod when a current ows through thecoil, substantially as described.

2. The combination in a resistance-coil, of a core of magnetic material,a coil of resistance material surrounding the same and contact-pieceselectrically connected to the coil and to the core, said pieces beingwithin the magnetic field set up from the said core when a current iowsthrough the coil, substantially as described.

3. A series of resistance coils, contactpieces therefor placed withinthe magnetic field of a current passing through said coils, the lines offorce of said field breaking any arc formed between said contact-pieces,sub= stantially as described.

4:. The combination in a resistance-coil of a body of insulatingmaterial, a rod of magnetic material passing therethrough, acontact-plate electrically connected to said rod, and a coil ofresistance material wound on the body of insulating material alsoelectrically connected to the rod, the contact-plate being within thefield of the current passing through the coil and the rod, substantiallyas de; scribed.

5. A series of resistance-coils,- each coil being provided with a coreof magnetic material to which it is'electrically connected, acontact-plate on each core, adjacent cores and their contact-platesbeing placed relatively near to each other whereby the magnetic fieldproduced when a current passes through one ofthe coils extends withinthe space between adjacent contact-plates, substantially as de# scribed.

6. The combination of a tube of insulating material, a rod of' magneticmaterial passing therethrough, a contact-plate fastened to the end ofthe rod, turns of resistance material wound on the said tube, and ametal plate electrically connected to the rod, one end of the coil ofresistance being connected to the plate, said plate being within themagnetic field set up through the rod when a current passes through thecoil, substantially as described.

7. The combination of a core of magnetic material, a slab of insulatingmaterial through which said core passes, a coil of wire wound on thecore and having one of its ends elec trically connected to -the same,means for clamping the core with its parts to the slab,

and a contact-piece detachably connected to an end of the core, the saidpiece being removable independently of all parts of the coil and core,substantially as described.

' S. A resistance-coil Wound around a core -of magnetic material andconnectedelectrically to said core at one end of the same, acontact-plate also electrically connected to the same end of the rodvand means at the other end of said rod formaking connection to anothercoil, the said magnetic core serving to direct the magnetic field when acurrent flows through the coil of 'resistance material, substantially asdescribed. n

9. The combination of a slab of insulating material, a resistance-coilhaving a core of magnetic material to which one of its ends is.

electrically connected, means for clamping said coil to said slab ofinsulating material, means for connecting the other end of the coil 1 toan adjacent coil and a contact-plate elec-

